UNIVERSITY OF WISCONSIN-LA CROSSE
Graduate Studies
MINI-TRAMPOLINES: DO THEY PROVIDE A SUFFICIENT AEROBIC
WORKOUT?
A Manuscript Style Thesis Submitted in Partial Fulfillment of the Requirements for the Degree of Master of Science in Clinical Exercise Physiology
Paige Burandt
College of Science and Health Clinical Exercise Physiology
December, 2016 MINI-TRAMPOLINES: DO THEY PROVIDE A SUFFICIENT AEROBIC WORKOUT?
By Paige Burandt
We recommend acceptance of this thesis in partial fulfillment of the candidate's requirements for the degree of Master of Science in Clinical Exercise Physiology
The candidate has completed the oral defense of the thesis.
~ Ifate
Carl Foster, Ph.D. Thesi mittee Member
Date I
Thesis accepted s~~~--~~~ Graduate Studies Director ABSTRACT
Burandt, P. Mini-trampolines: Do they provide a sufficient aerobic workout? MS in Clinical Exercise Physiology, December 2016, 48pp. (J. Porcari)
Purpose: To determine if a mini-trampoline exercise routine from Jump Sport met guidelines set by ACSM for improving cardiorespiratory endurance Methods: Twelve male (age 20.8 ± 2.09 years) and twelve female (age 20.7 ± 1.30 years) subjects performed a graded exercise test on a treadmill. Then subjects performed the selected 19 minute exercise routine on a mini-trampoline. Physiological responses, HR and V02 were monitored throughout. Perceived exertion was recorded every 5 minutes throughout the workout and at the end using the Borg 6-20 RPE scale. Results: It was found that both %HRmax (males: 77 ± 6.3 ; females: 80 ± 7.3) and %V02max (males: 58 ± 8.4; females: 61±6.7) met the guidelines of64-94% ofHRmax and 40-85% ofV02max set by ACSM. Throughout the workout subjects considered it to be of "light" intensity when using the 6-20 Borg RPE scale (males: 11.5 ± 2.0; females: 11.6 ± 1.24). Caloric expenditure for both males (12.4 ± 1.60 kcal/min) and females (9.4 ± 0.9 kcal/min) also met guidelines for weight loss. Males had a significantly higher energy expenditure than females due to higher body mass (184.0 ± 30.70 lb vs. 142.0 ± 13 .06 lb). Conclusion: The selected JumpSport routine does meet the standards set forth by ACSM to improve cardiorespiratory fitness and to stimulate weight loss.
iii ACKNOWLEDGEMENTS
To my parents, for instilling in me, from a very young age, the virtues of hard work, continuous education and caring for others. To my brother for his quiet, yet constant support from afar. To my best friends for their never-ending love and encouragement when I needed it the most. To my research assistant for keeping me grounded during all the crazy moments, and making me laugh during the tough ones. And lastly to my friends and family members who continued to believe in me, even when others no longer did.
iv TABLE OF CONTENTS
PAGE
ABSTRACT ...... iii
ACKNOWLEDGEMENTS ...... iv
LIST OF FIGURES ...... vi
LIST OF APPENDICES ...... vii
INTRODUCTION ...... 1
METHODS ...... 3
Subjects ...... 3
Procedures ...... 3
RESULTS ...... 5
Table 1. Descriptive characteristics of subjects ...... 5
Table 2. Average responses during the JumpSport workout, excluding the warm- up and cool-down ...... 6
DISCUSSION ...... 11
REFERENCES ...... 14
APPENDICES ...... 15
v LIST OF FIGURES
FIGURE PAGE
1. Heart rate responses of males and females over the course of the workout...... 7
2. %HRmax of males and females over the course of the workout...... 8
3. V02 responses of males and females over the course of the workout...... 9
4. % V02max of males and females over the course of the workout...... 10
vi LIST OF APPENDICES
APPENDIX PAGE
A Informed Consent Form...... 15
B. PAR-Q Form ...... 18
C. Data Collection Form...... 20
D. Borg RPE Scale ...... 22
E. Picture of Jump Sport Trampoline ...... 24
F. Review ofLiterature ...... 26
vii INTRODUCTION
Trampolines have been a popular form ofrecreation in the United States for over
50 years. They first emerged in 1936 as a recreational activity and sport, but have found a much wider range of uses. In WWII they were used in the training of fighter pilots
(Esposito & Esposito, 2009). Trampolines supposedly helped increase spatial awareness and balance abilities of pilots. After the war, their popularity soared with many gyms and schools sponsoring competitive teams. Once their international popularity increased, trampoline competition was introduced as an Olympic event (Esposito & Esposito, 2009).
Over the years a number of studies have been performed on the effectiveness of mini-trampolines as an exercise modality. In 1978, NASA concluded that trampoline training was as effective at aerobic training as running (Bhattacharya, McCutcheon,
Shvartz, and Greenleaf, 1978). The researchers examined the relationship between heart rate (HR) and oxygen consumption (V02) during running on a treadmill and jumping on a mini-trampoline. It was found that both modalities maintained a similar linear relationship betweenHR and V02. Additionally, there was no significant difference in submaximal V02 between the two exercises, leading to the conclusion that the energy requirements of jumping and running are similar. McGlone, Kravitz, and Janot (2002) also reinforced the effectiveness of jumping on a trampoline in comparison to running.
Their study found no significant differences in maximal HR, V02max or energy expenditure (kcal) when exercising on a mini-trampoline in comparison to running on a treadmill.
1 Conversely, Gerberich et al. (1990) had subjects perform incremental maximal
exercise tests on a treadmill and a mini-trampoline. Subjects achieved higher V02max values jogging on the treadmill compared to bouncing on the mini-trampoline. Edin et al.
(1990) conducted an 11-week training study using a mini-trampoline. They found no
significant differences in body weight, percent body fat, and lipid levels between the training group and the control group after the training program. Although the training
group did achieve a 4.4% improvement in their V02max, it was not statistically
significant.
Although many studies have looked at the effects of exercising on a mini trampoline, there is little data supporting its efficacy as a tool to increase
cardiorespiratory endurance and positively affect body composition. The American
College of Sports Medicine (ACSM) recommends exercising at 64-94% ofHRmax or 40-
85% of V02max 5 days/week for 30-60 min/day (ACSM, 2014). Although ACSM (2014)
does not have any caloric expenditure recommendations for the healthy adult, and earlier
article about weight loss stated that to stimulate weight loss it is recommended that a
person have a caloric deficit of 500-1000 calories/day with ~300 of those coming from
physical activity (ACSM, 2011).
Recently, fitness centers have begun offering group exercise classes, which lead
participants through a mini-trampoline based exercise routine. The purpose of this study is to determine the intensity of an individual mini-trampoline exercise routine and
compare it to the established guidelines by ACSM for cardiorespiratory endurance and
caloric expenditure.
2 METHODS
Subjects
Subjects for this study were 24 apparently healthy college students recruited from the UW-La Crosse campus. All subjects were recreationally active (exercising at least 3 times weekly for the past 6 months). Each subject completed a PAR-Q to screen for cardiovascular and orthopedic contraindications to exercise. Each subject provided informed consent prior to participating in this study. This study was reviewed and approved by the University of Wisconsin - La Crosse Institutional Review Board for the
Protection of Human Subjects.
Procedures
Initially, each subject completed an incremental maximal exercise test on a treadmill. Subjects walked on a motorized treadmill at a self-selected pace, which stayed constant throughout the test. The incline began at 0% grade and increased by 2.5% every two minutes and continued until volitional exhaustion. During this test, HR was monitored continuously using a Polar heart rate monitor (Polar Electro, Kempele,
Finland) and V02 was continuously monitored using an AEI metabolic cart (AEI
Technologies, Pittsburgh, PA). At the end of each stage and at maximal exertion subjects rated their perceived exertion using the 6-20 Borg (RPE) Scale (Borg, 1998).
Following completion of the V02 max test, subjects practiced various movements and choreography used in the JumpSport video (JumpSport Inc. San Jose, CA), to familiarize themselves with the activity. Subjects were able to practice on the mini-
3 trampoline until they felt comfortable. Once deemed proficient by the principle investigator, subjects completed a monitored trampoline exercise session while following the routine designed by JumpSport. The video was played on a computer screen for the subjects to watch and they were instructed to follow along with the routine. The routine was 19 minutes in length and incorporated a variety of movements to utilize the whole body. All sessions took place in the Human Performance Laboratory (HPL) on the UW
La Crosse campus. Throughout the exercise session, HR and V02 were measured in the same manner as the treadmill test and values were recorded every minute. Caloric expenditure was calculated from the V02 data assuming a constant of 5 kcal/liter of oxygen consumed. Rating of perceived exertion was assessed every 5 minutes during the workout using the 6-20 Borg scale.
4 RESULTS
The descriptive characteristics of this subject population are displayed in Table 1.
Table 1. Descriptive characteristics of subjects.
Males Females (n=12) (n=12)
Age (years) 20.8 ± 2.09 20.7 ± 1.30
Height (in) 69.9 ± 2.76 65.6 ± 2.05
Weight (lbs) 184.0 ± 30.70 142.0 ± 13.06
HRrnax (bprn) 182 ± 11.5 185±7.1
V02rnax (rnL/kg/min) 52.6 ± 8.53 48.2 ± 5.63
The responses to the workout portion of the JumpSport routine are presented in
Table 2 and Figures 1-4. The workout portion was defined as the middle 13 minutes. This excluded the first 3 minutes and the last 3 minutes, which were the warm-up and cool- down periods respectively. It was found that absolute HR %HRrnax, relative V02 and
% V02rnax were similar for both genders. Males burned significantly more calories than the females, due to their higher body mass.
5 Table 2. Average responses during the JumpSport workout, excluding the warm-up and cool-down.
Males Females Overall
HR(bpm) 141 ± 14.9 149 ± 14.1 145 ± 14.8
%HRmax 77 ± 6.3 80 ± 7.3 79 ± 6.9
V02 (ml/kg/min) 29.7 ± 1.69 29.1±2.33 29.4 ± 2.01
%V02max 58 ± 8.4 61±6.7 59 ± 7.6
Kcal/min 12.4 ± 1.60* 9.4 ± 0.90 10.9 ± 1.99
RPE 11.8± 1.05 11.6± 1.65 11.7± 1.36
Values represent mean ± standard deviation *significantly different than females (p < .05).
6 The average HR responses for each minute of the mini-trampoline routine are presented in Figure 1.
180 ~Males [- -<>Females 160
8 140 -Q. l-- ·· ·· -4~~--+--+---f- .c -.....QJ ~ 120 ~ .....;.. ~ 100 =QJ 80
60 I --i--.----r 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 ...... N ("') -.::t" tr) \0 t- 00 0\ 0 ...... N ("') -.::t" tr) \0 t- 00 0\ ...... Time (min)
Figure 1. Heart rate responses of males and females over the course of the workout.
7 Relative HR responses (%HRmax) of subjects during each minute of the mini- trampoline are presented in Figure 2. The boxed region indicates the current ACSM guidelines for improving cardiorespiratory fitness (64%-94% of HRmax).
100 -·,..------·-----···-·-·-·------
40
30 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 - N M -.::I" lF) l.O r-- 00 0\ 0 - N M -.::I" lF) l.O r-- 00 0\ _.Males Time- (min)------0-Females
Figure 2. %HRmax of males and females over the course of the workout.
8 The average V02 responses for each minute of the mini-trampoline routine are presented in Figure 3.
40 _.Males 35 -0-Females 30 -.5 ...... _e 25 ell .:;,:: ...... _ 20 ~e 15 -M 0 > 10
5 ·------·------·- ______,,,_,
---·1 ..... ,.-..,....-..- ..... ~...... ,...... l 0 ' r-·--,---,---,.... ·-· 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 ...... N ("') "<:!'" lrl ID r--- 00 0\ 0 ...... N M "<:!'" lrl ID r--- 00 0\ ...... Time (min)
Figure 3. V02 responses of males and females over the course of the workout.
9 Relative oxygen consumption responses (% V02max) of subjects during each
minute of the mini-trampoline are presented in Figure 4. The boxed region indicates the
current ACSM guidelines for improving cardiorespiratory fitness ( 40%-85% of
100 90 l-----~--···---· i ------...... ':~~:J = 80 70 ~ e~ 60 N 0 50 > 40 =~ 30 20 10 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 ...... N M "1'" i.n \0 r-- 00 ~ 0 ,...... N M "1'" i.n \0 t-- 00 ~ 1"""""4 1"""""4 1""""""( 1""""""( 1"""""4 1""""""( 1"""""4 1"""""4 Time (min)
Figure 4. %V02max of males and females over the course of the workout.
10 DISCUSSION
The purpose of this study was to determine if the mini-trampoline routine from
JumpSport met the guidelines set forth by ACSM for improving cardiorespiratory fitness.
American College of Sports Medicine (2014) currently recommends exercising at 64-
94% ofHRmax and 40-85% of%V02max to achieve these benefits. It was found that this routine does meet the recommendations as during the workout portion of sessions average HR was 79% of HRmax and average V02 was 59% of max. The only times spent outside the recommendations were during the warm-up and cool-down phases of the workout. In a previous study, Edin et al. (1990) found that subjects who completed an 8- week training program exercising on a mini-trampoline kept their heart rate between 70-
85% ofHRmax and increased their V02max by 4.4%. In this study subjects kept their
HR in a similar zone of 64-94% HRmax. Thus, the Jump Sport routine should provide a similar cardiorespiratory benefit.
Another method of determining relative exercise intensity is through the use of
RPE. During the workout portion of the DVD, males and females ranked the intensity of the exercise as 11.6 and 11.8 respectively. Based on the verbal anchor points of the Borg scale, this would classify the workout as "light" to "moderate".
Caloric expenditure is usually at the forefront of everyone's mind when evaluating new exercise modalities or regimens. American College of Sports Medicine
(2011) currently recommends burning 200-300 kcal during each 30 minute exercise session to result in weight loss or weight management. This recommendation
11 corresponds to burning 6.7-10 kcal/min. During the workout portion of this routine, males and females burned an average of 12.4 kcal/min and 9.4 kcal/min, respectively.
When including the warm-up and cool-down portions of the workout, males and females burned 11 .0 kcal/min and 8.3 kcal/min, for the 19 minute workout. Males burned more calories than females because of their higher body mass (184.0 lbs vs. 142.0 lbs).
Although Edin et. al. ( 1990) did not see any changes in body fat or blood lipids after an
8-week training program, this routine does produce a caloric deficit which should result in fat loss. This level of energy expenditure would be equivalent to running at a 6 mile per hour pace on flat ground or biking at 14 miles per hour. Other activities with equivalent intensities are basketball, football and ultimate Frisbee (Ainsworth, et al.
2000).
Future research may want to directly compare exercising on the mini-trampoline to other, more well-known, exercise modalities. This would be helpful so that exercisers can make informed decisions about its efficacy. The impact on one's joints could also be studied. Mini-trampoline exercise is attractive in that it is purported to be very low impact, but no evidence supports this to date. Balance is another area that this device claims improve, but there is no evidence to support that claim. Researchers may also consider looking into the enjoyabilty of this exercise modality. Although the data from this study supports it as physiologically beneficial, a modality is more likely to be used if subjects enjoy it.
Additionally, this routine was quite easy for subjects to learn. The majority of subjects needed only 10-15 minutes of practicing to feel comfortable with the routine and with using the mini-trampoline itself For this reason, we feel comfortable recommending
12 this modality to the general population even if they have not used a mini-trampoline previously.
In summary, we found that this mini-trampoline routine does meet ACSM standards for improving cardiorespiratory endurance. This mini trampoline routine elicited HR and V02 responses that were within ACSM (2014) guidelines. The caloric expenditure for both sexes was also above the minimal guidelines recommended by
ACSM (2011) for weight loss or management. This would make mini-trampoline exercise another enjoyable option for exercisers.
13 REFERENCES
Ainsworth, B.E., Haskell, W.L. , Whitt, M.C. Irwin, M.L. , Swartz, AM., Stratch, SJ., O'Brien, W.L. , Basset, Jr. D.R. , Schmitz, K.H., Emplaincourt, P.O. , Jacobs, Jr. D.R. , Leon, AS. Compendium of Physical Activities: An Update of Activity Codes and MET Intensities. Medicine & Science in Sports & Exercise. 2000.
American College of srorts Medicine. (2014). Guidelines for Exercise Testing and Prescription. 91 ed. Philadelphia: Wolters Kluwer/Lippincott Williams & Wilkins Health
American College of Sports Medicine Position Stand. Appropriate Physical Activity Intervention Strategies for Weight Loss and Prevention of Weight Regain for Adults. Medicine & Science in Sports & Exercise. 2011 .
Bhattacharya, A , McCutcheon, E.P., Shvartz, E., Greenleaf, J.E. Body Acceleration Distribution and 02 Uptake in Humans During Running and Jumping. Journal of Applied Physiology. 1978.
Borg, G. (1998). Borg's Perceived Exertion and Pain Scales. Champaign, IL: Human Kinetics
Edin, J.B. , Gerberich, S.G., Leon, AS., McNally, C., Serfass, R. , Shaw, G. , Moy, J. , Casal, D. Analysis of the Training Effects ofMinitrampoline Rebounding on Physical Fitness, Body Composition, and Blood Lipids. Journal of Cardiopulmonary Rehabilitation. l 990.
Esposito, P.W. and Esposito, L.M. The Reemergence of the Trampoline as a Recreational Activity and Competitive Sport. Current Sports M edicine Reports. 2009.
Gerberich, S.G., Leon, AS., McNally, C. , Serfass, R. , Edin, J.B. Analysis of the Acute Physiologic Effects of Minitrampoline Rebounding Exercise. Journal of Cardiopulmonary Rehabilitation. l 990.
McGlone, C. , Kravitz, L. , Janot, J.M. Rebounding: A Low-Impact Alternative. ACSM's Health and Fitness Journal. 2002.
14 APPENDIX A
INFORMED CONSENT FORM Informed Consent
Protocol Title: Mini-Trampolines: Do They Provide a Sufficient Aerobic Workout?
Principle Investigator: Paige Burandt Graduate Student University of WI-La Crosse (608) 293-3395
Emergency Contact: Paige Burandt (608) 293-3395
Purpose and Procedure: • The purpose ohhis study is to determine whether a mini-trampoline exercise routine meets American College of Sports Medicine guidelines for aerobic activity. • The trampoline routine that has been chosen is approximately 30 minutes in length and is designed to be of moderate intensity. • I will be asked to complete a graded, maximal exercise test on a treadmill. During this test I will be wearing a mask to analyze my expired air as well as a chest strap to measure heart rate. I will also be asked to rate my subjective exertion at the end of each stage using a Borg RPE Scale. • I will be asked to complete 3-5 "practice" trials on the mini-trampoline to become familiar with the routine and movements. • Once comfortable with the movements I will be asked to complete an incremental maximal test on a mini-trampoline. • I will then complete a monitored trampoline exercise session. During this monitored session my heart rate, expired air, and perceived effort will be monitored using the same methods as during the maximal treadmill test.
Potential Risks: • I may experience fatigue or leg soreness after completing the maximal treadmill test. • Falls are an inherent risk of trampoline use, but can be reduced with proper instruction and practice. • Other relatively minor injuries that can occur with trampoline use are: lacerations, contusions, fractures, sprains/strains of the lower extremities, concussions, and maxillofacial injuries. • Individuals trained in CPR, Advanced Cardiac Life Support and First Aid will be in the laboratory during all phases of this study, and the test will be terminated if complications occur.
16 Rights and Confidentiality: • My participation in this study is voluntary and I can withdraw from the study at any time for any reason without penalty. • All information will be kept confidential through the use of number codes and password protected computer files. The data gained from my participation in this study will not be linked to any personally identifiable information. • The results of this study may be published in scientific literature or presented at professional meetings using grouped data only.
Possible Benefits: • I will experience a new method of exercise. • I will gain knowledge about my current level of fitness. • I will be able to further appreciate the research process.
Questions regarding study procedures may be directed to Paige Burandt (608-293- 3395), the principal investigator, or the study advisor Dr. John Porcari, Department of Exercise and Sport Science, UW-La Crosse ( 608-785-8684 ).
Questions regarding the protection of human subjects may be addressed to the UW-La Crosse Institutional Review Board for the Protection of Human Subjects, (608-785-8124 or [email protected]).
Participant: ______Date: ------~
Researcher: Date: ------~
17 APPENDIXB
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!1'$~Wlli¥il~~! ~ttr>ify h i.111~1d:lJi!~;t,11..rn! ~ttt~lajfj 11\lltt !!filJ!t Wf ~ttt~R@l 111 !It(- W©rt ~M h'l:!l d4;. i\Uiflg :rm:m~ it!hi\i nWry ult ~ ~~ ~\!1!1t. Ho.,.~ :; i-ptcplt ~1'~1f &.tct ~lilhtir d!>C!ill' be!cn 11\ey ~Mrl lttw~ mU m JIG D D t , lfu put d(!dof -H.14tl!M .)'OU Im'•• hit•rt If YES to one or more questions 'fa:\ l'c'~,"tl -~ 4x~fr ~r tt4,~¢(d'>W~*"~ sevrt-y;, ~ it~n ~~N"\.~~1~ r@#t;.,~1""1~~ -mk•~ ·CE oc~ ~r..t:~ it f~ttt ~' OElAY llE(OMUfGMtlOI MO&ArnYe • MF'J¥t"41'Wl~i'itiltk';m.it¢ a~lfWtrf#'1t1H1JiLts i t~f0 iY' J, ~tr - wBt v~v f0'f~ tt# ·-ttrr~ tr ,$f~ t#. Mi¥i t:t f{'t{J\~h! .. ,,.. ttA; Vii fBf $.ikt :t 19 APPENDIXC DAT A COLLECTION FORM Sex: M F Subject#: ___ Name: ------Age: ___ years Height: ____ m Weight: ____ lb Treadmill: Testing Session: _____ at ___ Speed (mph): ____ Time Grade_i%~l RPE HR V02 0:00-2:00 0.0% 2:00-4:00 2.5% 4:00- 6:00 5.0% 6:00 - 8:00 7.5% 8:00 - 10:00 10.0% 10:00 - 12:00 12.5% 12 :00 - 14:00 15 .0% 16:00 - 18:00 17.5% 18 :00 - 20:00 20.0% 20:00 - 22:00 22.5% 22:00- 24 :00 25 .0% 24:00 - 26:00 27.5% 26:00 - 28:00 30.0% Trampoline: Testing Session: _____ at ___ RPE: 5:00--- 10:00--- 15 :00 ___ 20:00--- Final--- Comments: 21 APPENDIXD BORG RPE SCALE Rating Perceived Exertion 6 No exertion 7 Extremely light 8 9 Very light 10 11 Light 12 13 Somewhat hard 14 15 Hard 16 17 Very hard 18 19 Extremely hard 20 Maximal exertion 23 APPENDIXE PICTURE OF JUMPSPORT MINI-TRAMPOLINE 25 APPENDIXF REVIEW OF LITERATURE REVIEW OF THE LITERATURE Physiological Responses to Mini-Trampoline Exercise Trampolines have been a popular form of recreation in the United States for nearly 80 years (Esposito & Esposito, 2009). The first mini-trampoline prototype was created in 1936, but a patented version was not available to the general public until 1975. This made its full-sized cousin the king ofrecreational activities for over 40 years. George Nissen patented his full-size trampoline in 1936 and promoted it as a recreational activity, but is has found a much wider range of uses. Beginning in WWII, trampolines were used in the training of fighter pilots. Trampolines supposedly helped increase spacial awareness and balance abilities of these soldiers. After the war, their popularity soared with many gyms and schools sponsoring competitive teams. Trampolines became so popular that the first national championship was held in 1948. The public's fascination with trampolines only continued to grow and many families began purchasing full-sized trampolines for private use (Esposito & Esposito, 2009). However the mini-trampoline (also called a rebounder), didn't catch on with the public nearly as fast. In fact, it wasn't until 1977 when Albert E. Carter and his family of professional gymnasts toured the country performing their trampoline show that people began to take notice of mini-trampolines (Esposito & Esposito, 2009). Carter has been hailed as "the father of rebound exercise" partly because his show' s popularity, but largely due to the pamphlet "The Miracles of Rebound Exercise" that he published in 1979. This pamphlet, along with several studies extolling the benefits of mini- 27 trampolines, including one produced by NASA in 1978, were huge factors in the increase in popularity of the mini-trampoline (Esposito & Esposito, 2009). During the "aerobic craze" of the mid-80's mini-trampolines became a necessary accessory for fitness instructors and their participants. It is uncertain why the popularity of mini-trampolines in the fitness industry has faded, although there is speculation about the poor-quality of foreign made equipment that was saturating the market. Although mini-trampolines as an exercise modality had faded, its use for athletic competitions remained as high as ever. By 2000 their international popularity had reached its highest ever and trampoline competition was introduced as an Olympic event (Esposito & Esposito, 2009). Recently mini-trampolines have seen their popularity increase again as an aerobic training method. There are many recent studies that provide some evidence that mini trampolines are an effective exercise, but none have compared them to established standards for aerobic activity. Although Carter' s pamphlet sparked national attention, the first scientific study on mini-trampoline training was commissioned by NASA in 1978 and has become the go-to article for those claiming the benefits of rebounding (Esposito & Esposito, 2009). This is because its main finding was that trampoline training was as effective, if not more so, for aerobic training than running. This study was intended to study the effects of different exercises on persons subjected to a weightless environment for an extended time. The researchers were attempting to determine the best exercise to avoid deconditioning while astronauts were in space. The researchers studied eight young males. They analyzed the acceleration speeds at the subjects' heads, lower backs, and ankles as well as their heart rate (HR) and oxygen consumption (V02). They had subjects walk/run at four different 28 speeds on a treadmill while measuring acceleration, HR and V02. One week later subjects jumped on a trampoline at four different heights while the same measurements were taken. Researchers found that at similar HR and V02, jumping on a trampoline had a "greater biomechanical stimulus" than running on a treadmill. They also found that the impact on the lower body was lessened during trampoline training (Bhattacharya, McCutcheon, Shvartz, and Greenleaf, 1978). A later study had similar findings. This study was more focused on the effects of a mini-trampoline on body fat loss, but also measured V02max before and after their training program. The 60 overweight women who were subjects were randomly assigned to one of three exercise modalities: running, biking, or rebounding. Each group met 4 days/week for 10 weeks to perform 30 minutes of their assigned exercise. Post-testing results revealed that all three modalities resulted in lower body fat percentages as well as higher V02max (White, 1980). A more recent study by McGlone, Kravitz, and Janot (2002) compared effectiveness of trampolines in comparison to running. After monitoring the responses of 10 well-trained subjects, they found no significant differences in HR or V02. During this study subjects followed a trampoline routine lead by a certified instructor and rated it on Borg' s (1998) Rating of Perceived Exertion (RPE) scale. Later, subjects ran on a treadmill at 3% grade and self-selected speed. Subjects were instructed to select a speed that matched the RPE rating they assigned to the trampoline routine. Although there were no substantial differences between the two modalities, it was found that rebounding met ACSM guidelines of that time (2000) for aerobic activity. One main advantage of trampoline training is that it is low-impact. With jogging there is a great deal of impact 29 on one's body, but trampolines are able to absorb the vast majority of this shock (McGlone et al. 2002). Even with the support that rebounding has gained, there is still debate about the effectiveness of training on a mini-trampoline. Just as the mini-trampoline craze was fading in 1990, two studies were released stating that rebounding wasn't as effective as previously thought. Gerberich et al. (1990) looked at the effects ofrebounding in 17 sedentary women. Subjects performed two separate 18-minute graded exercise tests (GXT), one on a treadmill and one on a mini-trampoline. Stages were 3 minutes long and increased in intensity based on number of steps or bounces per minute. Researchers found that during the trampoline test, HR and V02 decreased as bounce frequency increased, whereas in the treadmill test HR and V02 increased with step frequency. This trend was also seen in the RPE during each test; on the trampoline RPE decreased as bounce frequency increased, and on the treadmill RPE values increased as step frequency increased. It was also noted that the V02max attained during the trampoline test was only 76% of the V02max achieved on the treadmill, and the V02max obtained from the trampoline test was 80% of the V02max from the maximal treadmill exercise test. From these findings it was determined that rebounding is actually less effective than jogging (Gerberich, et al. 1990). Also in 1990, Edin et al. researched the effectiveness of chronic mini-trampoline training. This team was specifically looking at changes in cardiorespiratory endurance, blood lipids, and body composition in sedentary women aged 18-40. The 17 subjects were randomly assigned to either an exercise or a control group. All subjects had a pre study health evaluation and GXT as well as blood tests to establish baseline 30 measurements. Subjects in the exercise group completed 11 weeks of training on the rebounder for 5 days/week. Exercise sessions consisted of two, 15-minute bouts of exercise with a 5-minute break. During exercise sessions, subjects jogged or bounced at a frequency sufficient to keep their HR in their established "training zone" (70-85% of HR max from GXT). Researchers found a small increase in V02max (4.4%) for the exercise group compared to the control group. However, there were no significant changes to blood lipids or body composition. Recently, mini-trampolines have seen a resurgence in their popularity as an aerobic training method, as more recent studies have attempted to evaluate its effectiveness. However, none of these studies compare the physiological responses to rebounding to established guidelines for aerobic activity. Mini-Trampoline Training in Athletes In a slightly different direction than the research of the past, Heitkamp et al. (2001) began looking at the strength increases that could be incurred by a balance training program without an accompanying strength-training program. Subjects were randomly assigned to either the balance-training program or the strength-training program. Those in the balance-training program performed exercises on a variety of instability devices, including the mini-trampoline. In the strength training group subjects performed strength exercise such as leg curls and leg press. After 6 weeks of training subjects had their balance and leg strength measured. After assessing the results, it was found that balance training on a variety of modalities, including mini-trampolines, resulted in increased balance and leg strength. The balance training also decreased strength imbalances between dominant and non-dominant legs (Heitkamp, et al. 2001). 31 Building off this idea, researchers began looking at the effects of trampoline training for male-gymnasts. Leg strength and balance are both key factors in the success in gymnastics. Atiligan (2013) examined both static and dynamic balance, as well as leg strength and vertical jump performances. The 28 subjects were randomly assigned to either the trampoline training group or the control group. The subjects in the trampoline training group followed a 1. 5 hour program taught by specialized instructors 2 days/week for 12 weeks. The subjects in the control group were not given any exercise to perform. This study found that the most significant improvement by the trampoline training group was in dynamic balance. This research suggests that trampoline training is most effective for the improvement of dynamic balance, rather than leg strength or static balance Karakolluk9u et al. (2014) took a different route of studying the physiological effects of rebounding. Specifically they examined the differences in physiological responses to trampoline exercise between collegiate gymnasts and non-athletes. This study included 20 collegiate gymnasts and 20 non-athletes. All subjects participated in a 12-week trampoline training program. After the training program was completed, subjects showed improvements in their standing long jump, vertical jump, 20-meter sprint speed and anaerobic power production. There was no change in the back strength of subjects after trampoline training. Special Populations The use of trampolines as a training method has been studied in a variety of special populations. Going back to a few years after its conception, trampoline training was used to train WWII fighter pilots. They found that training on a trampoline helped to improve the pilot's special awareness and balance, helpful when you're flying through 32 the air upside-down. A more recent study was performed on fighter pilots looking at training methods to reduce neck-strain. In this study, 16 volunteer Finnish Air Force cadets were randomly assigned to either the strength-training group or the trampoline training group. In the strength-training group subjects performed dynamic flexion and extension exercises and isometric rotation exercises. The trampoline training group performed multiple trampoline bouncing exercises. Subjects performed their assigned training routines for 6 weeks before being retested. There was decreased muscle strain in both groups. From this the researchers concluded that trampoline training and strength training were equally effective at reducing neck strain in fighter pilots. The author does note that since different muscles were more trained in each group, it would be advisable to use both strength training and trampoline training to most significantly reduce neck strain (Sovelius, et al. 2006). There is a great deal of interest in the use of trampolines in the treatment of cystic fibrosis patients. Since this population is relatively small there are only a few studies on this topic, but those that are have reported positive findings. It began with a small study by Stanghelle et al. (1988) which included only eight subjects. The subjects in the study were children with cystic fibrosis. Each subject participated in three short bouts (approximately 10 minutes) of trampoline exercise each day for 8 weeks. The researchers found that after the training there was a slight increase in FVC and a small, but notable, increase in V02max. Subjects were able to increase their V02max from 45 ml/kg/min to 49 ml/kg/min. It was suggested that trampolines be incorporated into the routines of those with cystic fibrosis to help avert monotony and boredom. 33 Even with this promising research, Barak et al. (2004) disagrees with systemically adding trampolines to the routines of cystic fibrosis patients. After examining the injury reports, he cautions about the risks to children with the use of trampolines. There have not been enough studies showing the benefits of trampoline therapy for children with cystic fibrosis. Until more research is produced, the potential risks of trampoline use appear to outweigh the potential benefits. Zolaktaf Ghasemi, and Sadeghi (2012) continued the exploration of mini trampolines as a therapy for patients with asthma. The 3 7 patients who participated in this study were randomly assigned to a control, rebound, or aerobic group. Subjects completed their assigned training regimen for 45-60 minutes, 2x/week, for 8 weeks. Pre and post testing was completed to measure for changes in FVC, FEVl, FEV1%, and V02peak. Post testing revealed that subjects in both the rebound group and the aerobic group improved on all measures while the control group did not experience any changes in their scores. It was also noted the rebound exercise group had greater improvements than the control group in all areas except FVC. Going back to looking at the benefits of trampoline training for athletes, Kidgell, Horvath, Jackson, and Semour (2007) evaluated athletes with ankle instability. Balance was assessed pre- and post-training by way of force plate. This machine analyzed the medial-lateral and the anterior-posterior sway paths to determine the stability of each subject. The 20 subjects were randomly assigned to the standard dura disc training group, the experimental mini-trampoline training group or a control group. Subjects completed 6 weeks of balance training on their assigned modality before being reassessed. It was 34 found that a balance-training program is as effective at reducing postural sway as the standard dura disc training program. Breaking from the young and well-trained, researchers began to examine the benefits of mini-trampolines for older populations. It is well known that tripping and falling can be very dangerous for older persons, often resulting in serious injury. Due to its well-documented balance-training abilities, Aragao, Karamanidis, and Arampatzis (201 1) evaluated mini-trampolines as a strategy to reduce this risk. This study had 22 elderly persons complete 14 weeks of mini-trampoline training, while 12 other subjects served as a control group. Researchers found the benefits of trampoline training to be two-fold. First, the training program increased the strength of plantarflexors in the feet, allowing the subjects to better pick up their feet and reducing the risk of catching their toes as they walked. Secondly, participants who took part in the training program were better able to regain their balance during stumbles helping to avoid a complete fall . Penzer, Duchateau, and Baudry (2014) built on this foundation of using mini-trampolines in the elderly. This team found that although balance training may be beneficial, its effects are increased when it is combined with a strength-training program. With all the information regarding balance training with mini-trampolines in the elderly, it was only natural to begin looking at stroke patients. Balance is a large concern for stroke patients due to the damage that occurs to the brain during a stroke. Not only did Miklitsch, Krewer, Freivogel, and Steube (2012) analyze the effectiveness of mini trampolines for this population, they compared it to standing balance program. In each group there was 20 subjects and all subjects participated in 10 sessions on their assigned balance routine. The mini-trampoline group completed their routine while on a mini- 35 trampoline, whereas the control group completed theirs while standing on the floor. Participants who completed the mini-trampoline routine had significantly increased postural control over those in the control group. Although not as significant, the mini trampoline also resulted in improved mobility. Both of these measures are associated with greater ability to complete activities of daily living. There has also been a lot of research done on the lymphatic system and how it is affected by rebounding. The lymphatic system brings nutrients to the cells and helps to clear away cellular waste, therefore it is very important that we keep it moving. Unfortunately, the lymph system does not have a constantly beating pump to circulate its fluid. It relies on movement, skeletal muscle contractions and gravity to make the fluid flow (Scrivens, 2008). The Textbook of Medical Physiology states that activity in the lymph system increases by 10-30 fold during exercise, but at rest it ' s almost nothing (Guyton & Hall, 2015). The movement as well as muscle contractions are certainly part of why rebounding is seen as one of the best exercises for lymph health. The other major factor that is specific to mini-trampoline training sessions is the effect of gravity. While bouncing your body is continuously being exposed to different amounts of gravitational forces, which also act like a pump helping the lymph system flow more efficiently (Scrivens, 2008). Risks Even with all the benefits available from trampolines, risk is still a factor for consideration. Although most trampoline injuries occur on full-sized trampolines, the risk for injury is still present on a mini-trampoline and must be addressed. An analysis performed by Steinbruck & Paelslack (1978) found that although over 7,000 trampoline- 36 related injuries occur each year, only a very small percentage of those are serious enough to require medical attention. The American Academy of Pediatrics (1999) had similar findings about the number and severity of trampoline related injuries. This report also makes note that a large proportion of injuries occur when participants are practicing tricks or stunts on the trampoline. Additionally, this report noted that many of the injuries from trampolining occur when there are multiple users on the trampoline simultaneously. Due to this risk of injury, several prominent organizations, including the American Academy of Pediatrics and the Canadian Pediatric Society, have released position statements cautioning the use of trampolines (American Academy of Pediatrics, 2015 and Canadian Pediatric Society, 2007). Britton, a Wisconsin Pediatrician, released a report on the dangers of falls to children (Britton, 2005). He stated that falls are the number one cause of injury to children. He highlights that trampolines are the 4th most frequent recreational activity to result in falls. The activities ahead of trampolines in these rankings are cycling, skateboarding, and roller blading. He does make a point that injuries sustained from falling from a trampoline are typically more severe due to the fact that they are higher off the ground than the other activities. The only article that addresses the risks associated with mini-trampolines was from Shields, Fernandez, and Smith (2005). They did a comparison of injuries sustained on mini-trampolines and full-sized trampolines over the course of 12 years. Their largest finding was that the vast majority of trampoline injuries happen to children. This analysis found that 82% of injuries from mini-trampolines and 90% of those from full-sized trampolines happened to children less than 18 years of age. They also found that the 37 group most at risk of injury from a mini-trampoline was children younger than 6 years old. This could be due to the fact that most full-sized trampolines come with a warning label that specifically warns against children under 6, whereas the warning labels on mini-trampolines don't always warn of their risk to children. Injuries resulting from the mini-trampoline were relatively minor when compared to those sustaining on a full-sized trampoline. They include head lacerations, contusions and fractures as well as lower extremity strains and sprains. 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